Coating apparatus



Dec. 15, 1942. R. F.- STRICKLAND ETAL COATING APPARATUS Filed Feb. 14,1940 r w /95 20 20/ 1 5? m 4 Sheets-Sheet l Inventor's Rogat F.Strickland,

.Fr-ank J. Mall og, Gerald W. Fbvall',

071 heir' Attorney.

Dec. 15, 1942. R, F. STRICKLAND El'AL 2,304,859

COATING APPARATUS Filed Feb. 14, 1940 4 Sheets-Sheet 2 Invencors:

Royal F. StrickLand, Frank J.MaLLo9,

er [d W. PovalL b Their- Attorneg.

COATING APPARATUS Filed Feb. 14, 1940 4 Shets-Sheet s ,U Ha ww m 5 aP wW H @5 m w n e m .n F

Inventors Rogal F. Strickland,

er" b Patented Dec. 15, 1942 COATING APPARATUS Royal F. Strickland andFrank J. Malloy, Cleveland Heights, and Gerald W.. Povall, EastCleveland, Ohio, assignors to General Electric Company, a corporation ofNew York Application February 14, 1940, Serial No. 318,962

.13 Claims. (Ciel-12.2)

Our invention relates to apparatus for coating a body or base memberwith reflecting materials, and more particularly to automaticallyoperable apparatus for causing the evaporation, in an evacuated space,of a reflecting material, such as aluminum, and its subsequentcondensation onto the interior surfaces of the vitreous enclosures orbulbs for incandescent lamps or similar articles.

Heretofore, as far as we are aware, the deposition of a metallicreflecting coating by vaporization onto a supporting body or base memberfor the coating material is injured and must be replaced before theapparatus can be used again. Other objects and advantages of ourinvention will appear from the following detailed description of aspecies thereof and from the accompanying drawings.

In the drawings, Fig. 1 is a plan view of apparatus comprising ourinvention with the major purposes of producing a specular reflector hasinvolved laboratory procedure and has been done in a relatively slowuneconomical manner. The principal object of our invention is to provideapparatus for this purpose having a high rate of production andrequiring only the feeding and the removal of the articles to be coated,and the insertion of the reflecting material. Such apparatus mustproduce a satisfactory reflecting coating with a high degree ofregularity in order to be commercially practicable.

Another object of our inventionis to provide apparatus for thesatisfactory coating of cupshaped vitreous bodies such as used for there-' flector sections of incandescent lamps of the type disclosed inPatent 2,148,314, D. K. Wright, assigned to the assignee of the presentinvention.

Such bodies are diflicult to coat evenly because of their shape, andmust have a very uniform coating because of their nearness to the lightsource which causes any defects to be very conspicuous.

Another object of our invention is to provide, in combination with theabove type coating apparatus, means for automatically preventing theheating of the reflecting material and thevconsequent vaporizationthereof should the space in which the vaporization takes place beimproperly evacuated. According to our invention, the supporting body orbase member to be coated is evacuated directly so that it, together witha portion of the apparatus, constitutes the vacuum chamber and'anyincorrect positioning of thesaid body or base member produces a leakingcondition. Such a condition may also be produced when, for some reason,one of said bodies has not been inserted in the apparams or 'when animperfect body which allows air to leak in is carried by the apparatus.Such a condition is objectionable because the quality of the vacuumaffects the distribution of the coating material to a considerableextent. Moreover, if the vacuum is poor enough, the heater forvaporizing portion of a turret, comprising part of the apparatus, brokenaway to show the underlying mech anism; Fig. 2 is a vertical section ofthe apparatus taken along line 2-2 of Fi 1; Fig. 3 is a horizontalsection, taken along the line 3-3 of Fig. 2, of one of a plurality ofheads carried by said turret; Fig. 4 is a perspective view, on anenlarged scale, showing a strip of metal, to be vaporized supported by aheater coil thereforev which is shown in dotted lines; Fig. 5 is an endview of a pinch clamp shut-off means provided for each head; Fig. 6 is aperspective view of the lower half of a rotary valve for controllingexhausting and gas filling operations of the head; Fig. '7 is a planview of operating means for a pinch clamp closing portion of a leakdetecting mechanism; Fig. 8 is a vertical section therethrough along theline 8--8 and in the directions indicated; Fig. 9 is a diagrammatic viewof a vacuum-quality testing mechanism and pinch clamp closing meansoperated thereby; Fig. 10 is a side view of the first three of a numberof contact-making mechanisms engaged by the heads, as viewed from lineIll-I0 Fig. 1; and Fig. 11 is a perspective view of switching means forcontrolling the operating period of the heaters in combination with adiagram of the other parts in the electrical circuit to one of saidheaters.

In the species of our invention shown in the drawings. a plurality ofheads l5 are provided for carrying the vitreous cups l6 through thevarious steps in the cycle of operation thereof. Only three of the headsl5 appear in Fig. 1, although a plurality (sixteen) of such heads aremounted at regular intervals at the periphery of the, two-part turretI'I which rests on the flange l8 (Fig. 2) of the hollow center column IQof the apparatus. The center column I 9 extends upward from stationaryframe 20 of the apparatus which spreads outward underneath the entirecenter portion of the turret I l as shown in Fig. 1 and is supported bythe engagement of the lower face of said flange l8 with the ball bearing2| on said frame 20. 'The motion of the turret ll occurs in repeatedindexing moveby a central driving means (not shown) which engages thelower end of the center column I9 and which provides for the operationof mechanisms at the various stations taken by the heads I6.

The cycle of operation of the apparatus begins at station A at which anoperator inserts a piece of the coating material to be vaporized and thevitreous cups I6 which are tobe coated. Each head I5 accommodates two ofthe cups I6 at one time and, accordingly, the operator first inserts abody 22 of the coating material into each of the two coiled portions23'-23' of the (tungsten) heater 23 (Fig. 3) which are located onopposite sides of the head I5. The body 22 of the coating material inthis particular instance, amounts to a thin strip of aluminum weighing.044 gram which, as shown in Fig. 4, is bent back on itself andcorrugated so that each corrugation engages a turn of the coil 23. Thesaid heater coils 23' are located along the central axis of the centralopening 24 in the ring or drum-shaped body portion 25 of the head I5.The ends of the heater 23, as shown in Fig. 3, are located in openingsin the split ends of the rods 26 which are drawn tight thereabout by thetapered sleeves 21 and are adapted to be easily removed therefromfollowing the unscrewing of the sleeves 21 to allow replacement of theheater 23. The rods 26 function both to support the heater 23 and carryelectrical energy to it and each rod is mounted in insulating bushings28. and 28' located respectively, in the threaded compression sleeve 29and an opening in the body portion 25 of the head I5. The said sleeves29 allow the rubber washers 30 and 3| to'be pressed against the flange26' on the rod 26 and seal the said opening in the body portion 25.

The vitreous cups I6, now inserted into the head I5, may be those usedfor the reflector section of a lamp of the type disclosed in WrightPatent 2,148,314, hereinbefore referred to. At this particular stage inthe manufacture of the lamp, each cup-is provided with a vitreousexhaust tube 32 sealed over an opening in the center of the end portionof the cup, and metal terminal elements 33 (two, in this instance)sealed over openings at diametrically opposite points on said endportion from the xhaust tube 32. The terminal elements 33 hermeticallyseal the openings in the cup I6 directly associated therewith, but theexhaust tube 32 does not, so that a stopper such as provided by therubber tube 34 which is closed off by the plug 35 is preferably slippedover the end thereof to seal the only remaining opening in the cup I6before it is inserted into the apparatus.

Insertion of each cup I6 is permitted only after the holder 36 is pulledback by pressure on the arm 31, and consists in resting the outer rim oredge of th cup against a rubber sealing gasket 39 on the face of the boy25 of the head I5. The holder 36 and the arm 31 are mounted on the rod39 carried by the bracket 40 and are then allowed to turn back so thatthe holder 36 engages said cup and keeps it in position. To allow thismovement of the holder 36, the cup I6 must be orientated so that thelowermost terminal element 33 falls in the center opening in the holder36. The closing movement of the holder 36 is produced by the contractionof the spring H which extends between a bolt in the lower part of thehead I5 and said holder 36 and does not change the position of thebracket 40 which is attached directly to the turret I1. The gasket 38 isheld in place on the body 25 of the head I5 by the ring 4| which isengaged by bolts screwed into said body 25 and extending through thegasket 38 and the ring 4 I The center aperture in the ring M is justlarge enough to allow easy passage of the outwardly flared edge I6 ofthe cup I6 and serves to position said cup so that the heater 23 is atthe exact center of the opening therein. The time interval of themovements of the turret I1 are such that the head I5 is moved to stationB directly following the insertionof both metal strips 22 and both cupsI6.

The indexing movement of the head I5 into station B starts the cycle ofoperation of the apparatus as the upper half 42 of the rotary valvewhich is located below the center of the turret I1 (Fig. 2) is turnedtherewith and connects a source of vacuum to said head I5. The hollowinterior of the body 25 of the head'I5, and the cups I6, are connectedto the rotary valve through the passage 43in said body 25 whichcontinues into the tube 44 extending downward through the turret I1, thepipe 45 which extendssidewardly from tube 44, the rubber tube 45 whichis part of the valve or pinch clamp 41, the pipe 48 and the rubber tube49 which makes the connection to the pipe nipple 49' extending from thepassage 50 in the upper half 42 of the rotary valve. Each head I5 issimilarly connected to a passage in the rotating upper half 42 of therotary valve which is made to turn with the turret I1 by the pin 5| anddepends on the movements of said upper half 42 with respect to the lowerhalf 52,

shown in detail in Fig. 6, for the proper sequence of operationsnecessary to clear the interior of the cups I6 of gas and vapor. Atstation B, the passage 50 is aligned with a passage 53 in the lower half52 of the rotary valve connected to a source of vacuum (not shown) andit is not until the head I5 is indexed to station C (only indi cated inFig. 1) that the succeeding operation also brought about by movement ofthe upper half 42 of therotary valve takes place.

The movement of the rotary valve occurring during this latter indexaligns the passage 58 with passage 54 which connects the head I5 to thevalve 55 of the pinch clamp closing apparatus shown in Figs. 1, 7 and 8and, asdiagrammatical- 1y shown in Fig. 8, to the manometer 56 whichmake up the leak detecting mechanism. These parts function only when thehead I5 is not closed off by the cups I6 as may happen for example, whenone or both of the cups I6 have not been inserted or have beenimproperly inserted therein or when an imperfect cup I6 produces aleaking condition. Should the head I5 be leaking, the mercury 51 in themonometer 56, which i already connected to one side of the electricalline by the wire 58, moves upward and into contact with the wire 59completing the circuit through the coil of the solenoid 60 which isconnected to the other side of the line by wire 6I. The solenoid 68 ismounted on the rod 62 extending from the bracket 63 on the frame 20through the bracket 64 and through movement of its armature 65 controlsall further operations of the leak detecting mechanism.

When the circuit to the solenoid 60 is closed and the armature 65 ismoved, the rod 66 is forced upward turning the arm 61, the shaft 68 onwhich it is mounted and the latch 69 so that the pulley 10 is freed andthe weight 1 I turns it in a counter-clockwise direction. The latch 69normally is located behind the notched block 12 on the pulley 10 inposition to prevent the weight 2,904,859 H which is attached thereto bythe chain 13 from turning said pulley 19. The pin I4 on which saidpulley 19 is mounted, the shaft 99 and the rod 99 are all mounted inportions of the bracket 15 attached to the rod 92. The rotative motionof the pulley 19 is transferred cases nrstca'rries the passage 99 in theupper half 42 ofthe-rotary valve connected to the head and turn the cam19 thereof which in turn forces I the lever 19 (Fig. 5) upward againstthe rubber tube 49 squeezing it shut. The cam 19 is pivoted on 'the pin99 between the front and back portions of the bracket II and is turnedso that the roller 92 on the pin 93 carried thereby is brought againstthe-lever 19 and the thicker portion of said cam 19 is carried intoposition between pin 99 and said lever 19. The lever 19 is also locatedbetween front and back portions of the bracket BI but is pivoted on thepin 94. The pin 95 functions as a stop and limits the movement of thecam 19 in both directions. In this manner, the leaking head I5 is closedoil and the influx of air into the evacuating system is stopped.

Operation of the valve 55 is brought about through the shaft 95 on whichthe lever 19 is mounted which extends downwardly to the disc 91 which itengages through the pin 89; Before operation of the leak detectingmechanism, the

disc 91 is arranged so that groove 89 (Figs. 7,

- and disc 91 be turned, the groove 99 is also carried over the otheraperture 92 in the bottom plate 9i and the source of vacuum connectedthereto draws out the air in the system back to the closed stop cock 41.In this 'way, the manometer 59 is returned to its open circuit positionin preparation for the resetting of the remainder of the leak detectingmechanism and the indexing of another head I5 into station B.

The resetting of the remainder of the leak detecting mechanism occursbefore the next index and is brought about by rotation of the vcam 93(Fig. 1) on the front cam shaft 94 in the lower portion of the frame 29.The cam shaft 94 is driven by the back main drive shaft 95 through thechain 96 and sprockets 91 and 98 indicated and .takes place in propertime relation to the other operations of the apparatus as the indexing.means (not shown) for the turret I1 is preferably operated thereby. Theroller 99 engaged by the cam 93 in resetting the mechanism is positivelyconnected to the operating shaft 96 of the lever 19 and the valve 55through the lever I99, link IM and arm I92 and is only in position to beengaged when the mechanism requires resetting. The bracket I93supporting the bottom plate 9I of the valve 55 and the pin I94supporting the lever I99 are attached to the frame 29. The disc 81 ispressed tightly against the bottom plate 9I to prevent leakage bythespring I95 which butts against the collar I99 on the shaft 99. i

In the course of the next two succeeding index- Il over a passage(either I91 or I99) which admits a flushing gas to the head I5 and thencauses it to come to rest over a passage (either I99 or II9) which isconnected to the evacuating means (not shown). The passages I91 and I99are connected in this instance to a supply of clean dry air, althoughnitrogen can be used equally as well for flushing if desired. Theevacuating means connected to passages I99 and H9 is preferably the sameas that connected to the head I5 at station 18.

. jects from the side of the tube 44 and is opened by a turning movementof the arm II3 (Fig. 1)

' which carries the roller 1 I4 against the cam III ing movements of thehead I5 which advance said head into station D and then E, repeatedflushing and exhausting operations are brought about providing the headI5 does not leak and pinch clamp 41 is not closed. The indexing in bothof said pinch clamp Ill. The pinch clamp III corresponds in constructionto the pinch clamp 41 adjacent which it is mounted and the arm II3engages and turrys the cam II5 thereof so that the lever H9 is allowedto move down and the rubber tube II2 can return to full round condition.The arm I I3 is mounted on the upper end of the shaft I" supported bythe frame 29 and is actuated by the following movement of the roller II9on the arm I I9 on th lower end of said shaft II1 along the face of camI29.

The cam I29 is mounted on the main drive shaft.

and the contracting force of the spring I2I which extends between a postin the frame 29 and the arm II3 causes the movement to occur as the camI29 permits.

Should the head I5 entering station F be open to the atmosphere asindicated by a closed pinch clamp 41, thepin I22 on the outer end of thelever 19 thereof will be in a lower position than normal and will engageand push the roller I23, (Fig. 1) back out of position. The roller I23isone part of the mechanism at this station which prevents the pinchclamp III from being opened and the exhaust system connected therefromfrom being contaminated by the influx of air under these particularconditions. As shown in Fig. 1, the roller I23 is mounted on the leverI24 which is mounted on the plate I25 extending from theframe 29 andwhich is turned so that it engages the control pin I29 of thetotallyinclosed switch I21. The lever I24 is normally turned by the contractingforce of the spring I29 which extends between one end thereof and a postin the plate I25 so that the stop screw I29 engages the end of theswitch I21 and when shifted causes said switch I21 to complete a circuitthrough the solenoid I39 -to the line. In

such cases. the armature of'the solenoid I39' which is connected to armI32 by a link I3I turns the arm I32, the shaft I33 on which it ismounted and the arm I34 so that the latter is lowered into the path ofmovement of the arm II 3 and prevents it from moving far enough to openpinch clamp III. The spring I35 which butts against the arm I34 andbracket I35 is compressed during this operation and the expanding forcethereof returns said arm I34 and the means connected thereto to theirnormal position when the head I5 is indexed from station F and theswitch I21 is permitted to open again. The solenoid I39 and the shaftI33 are supported by the -bracket 4 L I36 which is attached --totheirame 20 at this 7 point.

Following the opening of the pinch clamp III under normal conditions ofoperation, the head I5 and the cups I6-/I6 carried thereby are drawn onby the second exhaust system. This system includes a mercury pump I31(Figs. 1 and 2) for each head I5 which is connected to the rubber tube II2 of the pinch clamp III by the pipe I38 and through the pipe I39 tothe passage I40 in the upper half 42 or the rotary valve. The mercurypump I31 in general conforms to those shown in United States Patent1,676,302 to van der Poel which issued July 10, 1928, and is backed upby other exhausting means (not shown) connected to the passage MI inthelower half 52 of the rotary valve.

The mercury pumps I31 are operated by the effect of the electricalheating unit I42 in the lower portion thereof which is enclosed in theinsulated chamber I43 and the cooling effect of the water. in the tankI44 which is constantly being replenished from a source not shown andwhich overflows to the funnel I45 and pipe I46. The electrical currentfor the heating unit I42 is conducted thereto from the commutator I41which comprises the brushes I48 on the insulating bracket I49 carried bythe turret I1 and the metal rings I50 and I50 carried by the insulatingcollar I5I on the pipe I46. The rings I50 and I50 are engaged by thebrushes I48 which are pressed thereagainst by springs (not shown) andare the stationary members of the commutator as the pipe I46 extendsdown through the hollow column I9 to the frame 20 and a drain for thecooling water. The electrical connections to the rings I50 and'l50' aremade through wires (not shown) passing down'between the pipe I46 and thehollow column I9.

The exhausting operation of the second exhaust system is continuousduring the operation of the apparatus and the control and connection ofthe system to heads I5 depends on the pinch clamp III. As shown in Fig.6, a passage is provided in the lower half 52 of the rotary valvecorresponding to passage I at each station taken by the head I5 exceptbetween stations A to E inclusive where the slot I52 is provided forconnecting the mercury pumps I31 to another exhaust means so that theyare kept in proper functioning order at all times.

The indexing movement of the head I5 from station F to G wipes the cam18 of pinch clamp 41 on the stationary roller I53 causing it to turn andclose off the exhaust line controlled thereby so that said head I5, fromthis time on, is drawn on only by the second exhaust system. The rollerI53 is mounted on a yoke supported by the bracket I36.

No operation, other than the" exhausting of the head I5 by the secondexhaust system, occurs during the movements thereof from stations G toJ, but during the index from station J to K, the quality of the vacuumtherein is tested by the apparatus shown diagrammatically in Fig. 9. Thetest apparatus is divided into three parts, the first of which comprisesthe resistances I54, I55, I56 and I51 which are mounted in pairs in thevitreous envelopes I58 and I59 and which are connected in a Wheatstonebridge circuit with the resistances in each envelope in diagonallyopposite legs thereof. The envelope I59 is sealed except for the tubeI60 which, in 'combination with the rubber tube I62 and pipe I63,connects it to the interior of the head I5 whereas the envelope I58 ispreferably evacuated and sealed. Both envelopes I58 and I59 are mountedonthe turret l1 adjacent the 'head I5 so as to receive the same ambienttemperature changes and are provided with coiled tungsten resistanceslike those used as filaments in incandescent lamps. The current isintroduced in the bridge from the transformerI64 by the lead I65connected to the resistances I55 and I 51 and the potentiometer I66connected to the resistances I54 and I 56 which permits said bridge tobe balanced. Once the bridge has been balanced with the head I5 properlyevacuated, any improper condition of the vacuum causes heat to beconducted more rapidly from the resistances I56 and I51 to unbalance thebridge.

This unbalanced condition is not used except during the indexingmovement of the head I5 from station J to K when the brushes I61 and I68(Figs. 2, 3 and 9) which are mounted on the insulating block I69 at theperiphery of the turret I1 and which are connected-to the ends of theopposite arms of the bridgecontact the separated metal bands I10 and "Ion the stationary shoe I12. The shoe I12 is made of an insulatingmaterial and together with the vacuum tube amplifying means shownconnected thereto forms the second part of the test apparatus. Thismeans is mounted adjacent the-turret IT in a position not shown andamplifies the off-balance condition of the bridge so that it can causethe pinch clamp III andthe head I5 to be sealed from the second exhaustsystem if the vacuum is faulty. The amplifying means comprises thetransformer I13, the primary which is connected to the inetal take-offbands I10 and HI and the secondary of which is connected to cathode I14of the vacuum tube I15 and through the condenser I16 and the resistanceI11 to a grid thereof. The other parts of the amplifier comprise thetransformer I18 which is connected to the line and to the cathodeheating filament and which has a center tap on the primary connected tosaid cathode I14, the condenser I19 which is connected across thesecondary of transformer I13, the milliammeter I which is connected tothe plate of the vacuum tube I15 and the actuating coil of the relay I8Iand the condenser I82 and resistance I83 connected between the leadsfrom said coil. The plateuand third grid of the vacuum tube I15 areplaced at the proper potential by the lead I84 from one side of the linewhich is connected to the plate through the coil-of the relay I8I anddirectly to the third grid. The function of the parts of the amplifyingmeans is believed to be apparent Therelay I8I controls the operation ofthe third part of the test apparatus in that it completes the linecircuit to the solenoid I85 (Figs.

1 and 9) which indirectly raises the roller I86 so that the cam II5 ofpinch clamp III strikes it during the indexing motion and takes theclosed position. The armature I 81. of the solenoid I85 is connected tothe arm I88 on the shaft I89 by the link I90 and when actuated turnssaid shaftI89 so that arm, I9I andlink I92 are moved into alignment witheach other and lever I93 carrying the roller I86 is raised. The lever,ese 5 I is pivoted on tlie pin I84 held by the bracket which also holdsthe u er end f th 3 I95 extending from the frame 29 which also sup-.224. pp s o 8 8pm,

ports the shaft I89. Since the test apparatus only closes the pinchclamp III when a faulty head I5 is indexed into position, the secondexhaust system will normally continue to draw on raised in temperatureunder normal conditions.

The supporting rods 28 for the heater in each case are connected bywires to the studs I96 (Figs. 1 and 2) extending the insulating blockI91 on the turret I'I below each head I5 and the electrical connectionsare made thereto at each of the four stations by means engaging separatean ular contact surfaces of the blocks I98 on the lower ends thereof. Atstation K, as shown in Fi'gs. 1 and 10, the contacts I99 are carriedinto engagement with the blocks I98 by movement of the levers 299 andthe arm 29I on which they are mounted I and connect the secondary of thetransformer 292 shown diagrammatically in Fig. 11 thereto. The contactsI9 9 are insulated by suitable washers and sleeves from the levers 299which are pivotally mounted on the pin 293 carried by the arm '29I andwhich turn on said pin 293 against the contracting force of the springs294 to absorb the excess movement of arm 29!. Each spring 294 extendsfrom a post in a projecting portion of the arm 29I and through a passagetherein to the lowermost part of the lever 299 whose position prior tothe engagement of the contacts is established by the stop screw 295. Thearm 29I is mounted on a shaft 296 supported by the bracket 291 extendingfrom the frame 29 and is actuated from the shaft 298 which is similarlysupported by the bracket 299 and which is actuated by the engagement ofthe roller 2I9 on the lever 2I I with the cam 2I2 on the main driveshaft 95. The motion of shaft 298 is transferredto shaft 296 through thearms 2I3 and 2 on respective shafts which are Joined by the link 2I5.'At station L, levers 2I6 and the arm 2II which is mounted on the shaft298 perform the same function as levers 299 and arm 29I respectively,while at station M, levers 2I8 and lever 2II perform these functions. Atstation N, levers not shown corresponding to levers 2I8 and an arm onlypartially shown at 2I I corresponding to the upper part of lever 2Hcarry the contacts I99 into engagement with the blocks I98 and'the headI5.

At each of these stations K, L, M and N, electrical current does notpass through the heater operated in pairs by the cams 222 and 222 on aportion of the cam shaft 94 extending to the right farther than shown inFig. 1 and are turned about the pin 223by the contracting force of thesprings 224 under the direction of the following movement of the rollers225 on the forward end of levers 22I which engage said cams 222 and 222.The pin 223 is carried by the bracket 226 which is attached to anadjacent part of the frame 29 switch229 is tipped.

The switches 2 I9 which are in the line leads to the transformer 292are, as shown in Fig. 1, of totally enclosed form and are mounted on theframe 29 in position to be operated by the pinch clamp II I when thehead I5 takes positions K. L, M and N. If the head I! is not evacuatedto the degree desired, pinch clamp II I will have been closed onreaching these positions and the pin 22'! extending from the lever 8thereof will be lower than normal and will displace the levers 228 andoperate the switches 2I9. Normally. each switch 2I9 is closed and thelever 228 is turned about the pin 229 by the contracting force of thespring 239 to the limit allowed by the stop screw 23I but when the pin22! is down it engages the roller 232 on the end of said lever 228 andswings it against the control pin 233 of said switch 2I9.- Thisoperation opens the switch 2I9 and prevents the circuit from beingclosed when the mercury At station K, the heater is not raised to a.temperature high enough to vaporize the metal body 22 held by the coilsbut only to about 600 C. so as to drive, oil the moisture and dissipateany other type of contamination which can be carried off by the exhaustsystem. The control of this temperature is afforded by the rheostat 234in the primary circuit to the transformer 292. At the succeedingstations L, M and N, the heaters 23 are raised to about 2000 C. and insome instances even to a higher temperature so as to heat the bodies 22of metal in the coils 23' thereof and cause them to be vaporized. Thevaporizing of the metal takes place very rapidly and in most instancesis completely brought about before the head 'I5 enters the last flashingstation. As the heater coils 23'-23' are at approximately the centers ofthe cups I5- I8, the vaporized metal condenses on the interior thereofin a relatively uniform deposit which forms a very efllcient lightreflecting coating. The proper distribution of the metal over theinterior of the cups I8 is assisted'by the baflies or partitions 235-235which 3 apparently prevent the metal vaporized by one heater coil fromdepositing on the cup on the opposite side of the'head I5 and assist inthe proper withdrawing of the atmosphere and impurities from the spaceadjacent the rim of the cups I8I6. The baffles 235235 whlchar'e thesubject matter of a separate application of Carl Lenz Serial No. 318,963filed February 14, 1940, engage the gaskets 38-38 and the body 25 of thehead I 5 and are held in place by the spring clip 235.

Following the last flashing operation and the indexing movement of thehead I5 from station N, the cam II5 of pinch clamp III moves against thestationary roller 231 (Fig. l) and said pinch clamp III is closed. Theroller 231 is held by a yoke carried by the bracket-238 extending fromthe frame 29. By closing off the pinch clamp I I I,

the second exhaust system is permanently stopped from drawing on thehead I5 at any further time in this cycle of operation of the apparatus.

Station 0 is an idle station and it is not until the head I5 is indexedinto station P that the next and final operation of the apparatus takesplace. At station P, the pinch clamp 41 is opened by movement of theroller 239 on the lever 249 against the cam 18 thereof which is shiftedso that the dry air connected thereto through the rotary valve isallowed to enter the head I5 and the cups Iii-I6. The lever 249 ispivoted on a pin projecting from the, frame 29 and is actuated by theinterconnected arms 2 and 242, the lat- 1 ter of which engages saidlever 240 through the link 243 and the former of which is connected tothe lever 244 by the rod 245. 'The lever 244 is pivoted on a pinextending from the frame and is operated by the face or box cam 246 onthe'cam shaft 94 which it engages through the roller 241. The dry air isconducted through the pinch clamp 41 at this time since the passage 50in the upper half 42 of the rotary valve is now aligned with the passage248 (Fig. 6) in the lower half 52 thereof which is connected to thesource of supply of said air (not shown) The entrance of the dry airinto the cups Hi -l 6 allows them to be easily removed at station Q bythe operator after the holders 36 and 36 have been moved back.

What I claim as new and desire to secure b Letters Patent of the UnitedStates is:

1. Apparatus for depositing a reflecting coating on the inner surfacesof a pair of cup-shaped bodies comprising a hollow head member havingside portions each shaped to engag and form an air-tight seal with theedges of said cup-shaped bodies and having a connecting passage Iorpermitting the space enclosed by said bodies to be exhausted, andelectric heater coils mounted within said head and projecting into thespace enclosed by said bodies along the axis through said head andbodies, and means for heating said coils to vaporize bodies of thcoating material placed located in said opening, a carrier for advancingtherein so that the vapor condenses on the inner base member is placedand a connecting passage for permitting said opening and the spaceenclosed by said basemember'to be exhausted, electrical heating meansmounted on the head in the opening therein and arranged to carry aquantity of vaporizable coating'material, means for connecting saidheating means to a source of current to preliminarily heat it to adegree insuflicient to vaporize said coating material but suflicient toexpel contaminating substances from the heating means and from thecoating material associated therewith, said contaminating substancesbeing withdrawn through said connecting passage, and means forsubsequently causing said heating means to be heated sufficiently tovaporize the coating material so that it condenses on the surface ofsaid base member.

3. Apparatus for depositing a reflecting coating on the surface of abase member comprising a head having an opening therein over which saidbase member is placed, electrical heating means located in said openin acarrier for advancing the head to a plurality of stations in turn, anexhausting means, means at at least one of said stations for connectingthe opening in said head and the space enclosed by said base member tosaid exhausting means, a second exhausting means mounted on thecarrienmeans for .eonnecting said second exhaust means to said head at afollowing station, and means, operable upon movement of said carrier,for i connecting the heating means of said head to a source of currentat another station for vaporizing a body.of the coating materialassociated therewith so that it condenses on the surface of said basemember.

4. Apparatus for depositing a reflecting coating on the surface of abase member comprising a head having an opening therein over which saidbase member is placed, electrical heating means thehead toia pluralityof stations in turn, means controlled by the movements of the carrierand connected to the opening in said head for causing a preliminaryexhausting, a flushing and then a more: complete exhausting of saidopening and the space enclosed by said base member, and means, operableupon movement of said carrier, for connecting the heating means of saidhead to a source of current at another station for vaporizing a body ofthe coating material associated therewith so that it condenses on thesurface of said base member.

5. Apparatus for depositing a reflecting coating on the surface of abase member comprising a head having an opening therein over which thebase member is placed, electrical heating means located in said opening,a carrier for advancing the head to a plurality of stations in turn, anexhaust means, means including a valve mounted on the carrier forconnecting the opening in said head and the space enclosed by said basemember tosaid exhaust means, means located along the .path of movementof the carrier for opening and closing said valve at different pointsalong said path, a second exhausting means mounted on said carrier,means including a second valve for connect ing said head and said secondexhausting means together, means located further along the path ofmovement of the carrier for opening and closing the said second valve inorder at different points along said path, and means, operable uponmovement of said carrier, for connectingsaid heating means to a sourceof current at another station for vaporizing a body of the coatingmaterial associated therewith so that it condenses on the surface ofsaid base member. I a

6. Apparatus for depositing a reflecting coat-' ing on the surface of abase member comprising a head having an openin therein over which thebase member is placed electrical heating means located in said opening,a carrier for advancing the head to a plurality of stations in turn, anexhausting means, means at a plurality of said stations for connectingthe opening in said head and the space enclosed by said base member tosaid exhausting means, means for connecting said heating means to asource of current at another station for vaporizing abody of the coatingmaterial associated therewith so that it condenses on the surfaces ofsaid base member, means at one of said exhausting stations for testingthe quality of the vacuum held by the head and for closing off theconnection thereto when unsatisfactory vacuum is indicated, and means,operable upon the closing ofi' of said vacuum connection, for preventingthe completion of -the electrical circuit to the said heating means. v i

7. Apparatus for depositing a reflecting coating on the surface of abase member comprising,

a head having an opening therein over which the base member is placed,electrical heating means located in said opening, a carrier foradvancing the head to a plurality of stations in turn an exhaustingmeans, means at a plurality of said testing the quality of the vacuumheld by the head and for closing oil the vacuum connection thereto whenunsatisfactory vacuum is indicated, a displaceable member mounted on thecarrier and arranged to be repositioned by the closing off of saidvacuum connection, a normally closed switch located at the same stationas the said electrical connection-making means and connected in thecircuit thereto, and means mounted adjacent the said switch and engagedby said displaceable member when it is repositioned for opening the saidswitch and preventing the completion of the electrical circuit to thesaid heating means.

8. Apparatus for depositing a reflecting coating on the interiorsurfaces of a plurality of cupshaped bodies comprising a rotatableturret, a plurality of heads mounted at the periphery of the turret,each of said heads having an opening therein over which one of saidbodies is placed and electrical heating means located in said opening,means connected to said openings in the heads and the spaces enclosed bysaid bodies for permitting the exhausting thereof during the rotation ofthe turret, and means located adjacent the periphery of the turret forconnecting the heatin means of a plurality of heads in turn to a sourceof current, upon rotation' of said turret to vaporize a body of thecoating material associated therewith so that it condenses on the innersurfaces of said cup-shaped bodies.

9. In a device of the class described, a hollow head member having sideportions shaped to engage and form an air-tight seal with the edges of aplurality of bodies held thereagainst in opposed relationship wherebythe said hollow head member and said bodies conjointly form an airtightenclosure, an exhaust connection to said head member, means carried bysaid head member within said enclosure for supporting a quantity ofvaporizable coating material, and means for heating said last-mentionedmeans to vaporize said coating material so that it condenses on thesurfaces of said bodies.

10. In a device of the class described, a hollow head member having sideportions shaped to engage and form an air-tight seal with the edges of apair of bodies held thereagainst in opposed relationship whereby thesaid hollow head member and said bodies conjointly form an air-tightenclosure, an exhaust connection to said head member, means carried bysaid head member within said enclosure for supporting a quantity ofvaporizable coating material adjacent each of said bodies, and means forheating said lastmentioned means to vaporize said coating material sothat it condenses on the surfaces of both of said bodies.

11. In a device of the class described, a head comprising a hollowring-shaped portion having its opposite sides shaped to engage and forman air-tight seal with the edges of a pair of bodies held thereagainstin opposed relationship whereby the said ring-shaped portion and saidbodies conjointly form an air-tight enclosure, an exhaust connection tosaid ring-shaped head portion, means carried by said ring-shaped headportion within said enclosure for supporting a quantity of vaporizablecoating material, and means for heating said last-mentioned means tovaporize said coating material so that it condenses on the surfaces ofboth of said bodies.

12 In a device of the class described, a head comprising a hollowring-shaped portion having its opposite sides shaped to engage and forman air-tight seal with the edges of a pair of bodies held thereagainstin opposed relationship whereby the said ring-shaped portion and saidbodies conjointly form. an air-tight enclosure, an exhaust connection tosaid ring-shaped head portion, conductive support members extending intothe interior of said ring-shaped portions from opposite sides thereofand transversely of the axis thereof, and an electrical heater elementwithin said ring-shaped head portion supported at its ends by, andelectrically connected to, said support members, said heater elementbeing constructed and arranged to support and vaporize a quantity ofvaporizable coating material so that it condenses on the surfaces ofboth of said bodies.

13. In a device of the class described, a head comprising a hollowring-shaped portion having its opposite sides shaped to engage and forman air-tight seal with the edges of a, pair of bodies held thereagainstin opposed relationship whereby the said ring-shaped portion and saidbodies conjointly form an air-tight enclosure, an exhaust connection tosaid ring-shaped head portion, conductive support members extending intothe interior of said ring-shaped portion from 0pposite sides thereof andtransversely of the axis thereof, and an electrical heater elementwithin said ring-shaped head portion supported at its ends by, andelectrically connected to, said support members, said heater elementcomprising intermediate portions extending substantially axially of saidring-shaped head portion and beyond the said sides thereof, saidintermediate heater portions being constructed and arranged to supportand vaporize a quantity of vaporizable coating material adjacent each ofsaid bodies to thereby coat both of said bodies.

ROYAL F. STRICKLAND. FRANK J. MALLOY. GERALD W. POVALL.

